/Engine/Plugins/Experimental/MeshModelingToolsetExp/Source/MeshModelingToolsEditorOnlyExp/Public/AttributeEditorTool.h
Remove any hard edges / split normals, setting all normals to a single averaged vertex normal
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(CallInEditor, Category=Normals, Meta=(DisplayPriority=1)) void ResetHardNormals()